Display screen or portion thereof with a graphical user interface



The sole FIGURE is a front elevational view of the display screen orportion thereof with a graphical user interface in accordance with thenew design.

The broken lines showing the display screen or portion thereof and thebroken lines showing the remainder of the graphical user interface arefor environmental purposes only and form no part of the claimed subjectmatter.

CLAIM The ornamental design for a display screen or a portion thereof with a graphical user interface, as shown and described. 